 Facts and figures about UK taxes, benefits and public spending.
Income distribution, poverty and inequality.
Analysing government fiscal forecasts and tax and spending.
Analysis of the fiscal choices an independent Scotland would face.
Case studies that give a flavour of the areas where IFS research has an impact on society.
Reforming the tax system for the 21st century.
A peer-reviewed quarterly journal publishing articles by academics and practitioners.
|
Type: cemmap Working Papers Authors: Xiaohong Chen, Jinyong Hahn and Zhipeng Liao
JEL classification: C14, C31, C32 Keywords: Overlapping information sets, semiparametric efficiency, two-step GMM
In this note, we characterise the semiparametric efficiency bound for a class of semiparametric models in which the unknown nuisance functions are identified via nonparametric conditional moment restrictions with possibly non-nested or over-lapping conditioning sets, and the finite dimensional parameters are potentially over-identified via unconditional moment restrictions involving the nuisance functions. We discover a surprising result that semiparametric two-step optimally weighted GMM estimators achieve the efficiency bound, where the nuisance functions could be estimated via any consistent non-parametric procedures in the first step. Regardless of whether the efficiency bound has a closed form expression or not, we provide easy-to-compute sieve based optimal weight matrices that lead to asymptotically efficient two-step GMM estimators. Search |
|
|
|
© The Institute for Fiscal Studies
Limited by Guarantee,Registered in England: 954616 7 Ridgmount Street London WC1E 7AE Registered Charity: 258815 VAT no: GB 394 5830 17 Website design by Pynk and Fluffy |
||||||
